Taiwanese researchers take aim at environmental issues

NTU is also aiming to save the world's honey bees, which are dying in droves due to unknown causes, threatening the pollination of crops worldwide, which is estimated to be devastated by 2035 if the problem is not solved. NTU's solution is to create a special radar to track honey bees—a cooperative effort between its Graduate Institute's of Communications Engineering (GICE) and Biomedical Electronic and and Bio-Information (BEBI), in consultation with the Department of Entomology.

The problem is that honey bees are dying off, but no one has been able to reliably track where they were located when they encountered the cause of their death, nor its precise mechanism. Other groups have tried to track bee movements with bulky centimeter-long antennas that prevented them from re-entering the hive, thus limiting the trackers usefulness to a single foraging trip. That's when bee-expert En-Cheng Yang came to IEEE Fellow Huei Wang to ask for help.

Wang and his team, including professors Kun-You Lin and Fan-Ren Chang, have designed a passive harmonic radar transponder that measures in millimeters and weighs just milligrams. After the transponder is glued to a bee's back, they fly off about their business as usual—making all their routine foraging runs between pollen sources and the hive, all the while leaving a radar trace on the team's monitors.

Honey bees do not even seem to notice the millimeter sized radar transponders which weigh mere milligrams, but which allow scientists to track their movements, hopefully tracking down the source of the scourge on their dwindling populations.

Because the signal returned from the transponder is so weak—often far below the noise level of the environment—the team had to design a special code based on shift-key modulation, which the transponder echoes at double the broadcast frequency, allowing the radar to more easily pick the unique code out of the noise.

Currently the receiver is a large commercial unit with a range of only 60 meters, limiting its usefulness to regions close to the hive. However, the team is now designing a hand-held unit which will allow investigators to follow the bees where ever they go, hopefully leading to a positive identification of the source of the bee's misery in time to save the world's agriculture.